Pubcookie is an Open Source package for intra-organizational, end-user authentication and Web single sign-on. More generally, it is an approach to identifying users as they browse to an organization's many Web sites that require authentication.

Pubcookie is a protocol and a software package for providing single sign-on within web applications and websites of an organization. An untrusted web application authenticates the end user against a trusted authentication server via a trusted login server. The Pubcookie software is open source and licensed under the Apache License.

Internet2 sponsored project from the University of Washington to provide WebISO.